The present invention is related to a hand tool, and more particularly to a box-end wrench. A resilient ring is disposed in the box end. The diameter of the resilient ring is changeable, whereby the wrench is capable of clamping a screwed member and preventing the screwed member from slipping out of a socket of the wrench. Also, the wrench permits the screwed member to freely pass through the socket.
A conventional box-end wrench has a polygonal socket for fitting onto a screwed member such as a nut or a bolt and wrenching the same. The polygonal socket passes through the box end of the wrench so that the screwed member is easy to slip out of the socket. Accordingly, the box end of the wrench is generally formed with a stop structure for preventing the screwed member from slipping out of the socket. However, when fitting the wrench onto the screwed member, the stop structure disables the screwed member from freely passing through the socket.